The present invention relates to semiconductor devices and methods of fabrication therefor, and more particularly, to nonvolatile memory devices and methods of fabrication therefor.
Field effect transistors (FETs) are widely used in integrated circuit memory devices. These field effect transistors may include metal oxide semiconductor FETs (MOSFETs) and variants thereof, such as floating gate transistors. A typical floating gate integrated circuit field effect transistor includes spaced apart source and drain regions, an active (channel-supporting) region therebetween and a gate structure including a tunnel oxide layer on the channel, a charge-retaining layer on the tunnel oxide layer, a dielectric layer on the floating gate layer, and a control gate electrode on the dielectric layer.
There has been an ever-present drive to increase the amount of memory capacity that can be provided in a given amount of space. Thus, the size of memory cells has been decreased. In addition, cell architectures that can increase effective use of wafer area, such as stackable cell architectures, have also been employed.